1. Field of the Invention
The present invention relates in general to a propeller shaft support mechanism for use in an automotive vehicle of the kind having a chassis and a body resiliently supported on the chassis, as for example a truck, and more particularly to a center bearing and support mechanism for a two-piece or three-joint propeller shaft for use in a truck or the like vehicle.
2. Description of the Prior Art
An example of a prior art center bearing and support mechanism for a two-piece pro peller shaft requiring three universal joints for its connection is disclosed in Japanese Provisional Utility Model Publication No. 58-90381 and also shown in FIGS. 3 and 4. The mechanism includes a ball bearing 13 mounted on a two-piece propeller shaft adjacent a center universal joint and an insulator 14 made of soft resilient rubber. The bearing 13 and insulator 14 are supported on a vehicle frame 12 via an upper bracket 15 and a lower bracket 16.
With the prior art center bearing and support mechanism, variations of the angles of the universal joints cause a secondary couple from which vibrations of the propeller shaft 11 result. Such vibrations are transmitted through the bearing 13 and the insulator 14 to the vehicle frame 12, thus deteriorating the riding comfort of the vehicle. Vibrations transmitted to the vehicle frame 12 are enhanced upon acceleration of the vehicle at which the angles of the universal joints become larger. In the case of a truck in which a cab is resiliently supported on a chassis, such vibrations are transmitted to the cab. In order to solve the above problem, dynamic dampers can be used successfully. This however results in the increased weight of the vehicle.